The vast majority of pregnant mothers in the USA have multiple chemicals inside them, including some that have been banned for over thirty years, Californian researchers revealed in Environmental Health Perspectives. The authors expressed surprise that so many chemicals were found in pregnant women, bearing in mind that there is very little we know about what impact they may have on the mother and developing baby.
This is the first study to count how many chemicals American pregnant mothers are exposed to, the authors added.
The research team assessed data from NHANES (National Health and Nutritional Examination Survey) 2003-2004 on 268 pregnant mothers - a nationally representative sample of the American population.
The scientists gathered data on 163 chemicals and found the following chemicals in 99% of pregnant women:
- PCBs (polychlorinated biphenyls) - a mixture of up to 209 chlorinated chemicals. No longer produced in the USA, but still exist in the environment. They have been used as coolants and lubricants in capacitors, transformers and other electrical equipment. Goods manufactured before 1977 in America may contains PCBs. People exposed to large amounts can suffer from skin conditions, such as acne and rashes. Some studies have linked PBC exposure to a higher risk of developing some cancers. Pregnant women exposed to high levels have been found to have newborns who weigh less than normal. Some behavioral and cognitive problems were found in babies born to mothers who ate PCB-contaminated fish.
- Organochlorine pesticides - DDT (dichlorodiphenyltrichloroethane) is an organochlorine pesticide which was banned in the USA in 1972.
- PFCs (perfluorinated compounds) - these compounds have unique properties to make materials stain, oil, and water resistant. They can be used to make fluoropolymers, such as Teflon, perfluorooctanesulfonic acid used in the semiconductor industry - Scotchguard (3M formula) contains PFCs, as well as 3M's former fire-fighting foam mixture. PFCs have many other applications.
- Phenols - some phenols may possess endocrine disrupting and estrogenic activities.
- PBDEs (polybrominated diphenyl ethers) - compounds used as flame retardants, banned in California and many US states.
- Phthalates - compounds added to plastic to make them more flexible, transparent and durable. The USA, Canada and the European Union are phasing them out due to health concerns.
- PAHs (polycyclic aromatic hydrocarbons) - potent atmospheric pollutants. Some compounds have been identified as carcinogenic (cause cancer), mutagenic (can alter genetic material), and teratogenic (can cause abnormalities of physiological development).
- Perchlorate - salts derived from perchloric acid (HClO4) which can occur both naturally and through manufacturing. Used in medicine for over five decades to treat disorders of the thyroid. Used widely in the pyrotechnics industry. It is also a component of rocket fuel. It can undermine human health by interfering with iodine uptake into the thyroid gland.
The authors stress that their aim was to identify how many chemicals pregnant mothers were carrying, and not to assess what effect they might have on the mother's and baby's health.
Tracey Woodruff, PhD, MPH, director of the UCSF Program on Reproductive Health and the Environment, said:
"It was surprising and concerning to find so many chemicals in pregnant women without fully knowing the implications for pregnancy. Several of these chemicals in pregnant women were at the same concentrations that have been associated with negative effects in children from other studies. In addition, exposure to multiple chemicals that can increase the risk of the same adverse health outcome can have a greater impact than exposure to just one chemical."
Previous research has shown that exposure to some chemicals during fetal development can:
- Increase the risk of premature birth
- Raise the likelihood of being born with birth defects
- Increase childhood morbidity
- Make it more likely that the baby develops certain diseases later on in life
- Influence the baby's lifespan
"Our findings indicate several courses of action. First, additional research is needed to identify dominant sources of exposure to chemicals and how they influence our health, especially in reproduction. Second, while individuals can take actions in their everyday lives to protect themselves from toxins, significant, long-lasting change only will result from a systemic approach that includes proactive government policies."
"Environmental Chemicals in Pregnant Women in the US: NHANES 2003-2004"
Woodruff TJ, Zota AR, Schwartz JM
Environ Health Perspect 2011 doi:10.1289/ehp.1002727
Written by Christian Nordqvist